After the files are missing, the temporary files will appear in the missing folder.
Temporary file names will be something like" atmp9454" , or "savE5F5.tmp"
Just choose one of the files above, and change the file extention to ".dwg" (i.e.: atmp9454.dwg)
Then you will recover your missing file.
It worked for me, I hope it will work for you too!
I also am working with AuotCAD 2012 and getting a HUGE amount of ATMP files. Today I came in and my .DWG was totally missing and I had to look at the timestamp of the ATMP to determine which was my latest.
AUTODESK THIS HAS BEEN A BUG FOR YEARS!!!! FIX YOUR CODE ASAP!
Your moto shouldn't be "IF IT'S BROKE, DON'T FIX IT." leave that one to Microsoft.
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